Amplifier



FIG. 1 is a perspective view of an amplifier showing the new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right-side view thereof;

FIG. 5 is a left-side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines in the drawings illustrate portions of the amplifier that form no part of the claimed design. 

CLAIM The ornamental design for an amplifier, as shown and described. 